Granule, method for producing the granule, and feed mixture

Abstract

The invention relates to a granulate whose granule particles comprise cellulose-containing fibers. The granulate according to the invention is characterized in that the granule particles are able to absorb at least their own weight in a liquid substance while simultaneously maintaining their flowability.

Description

[0001] The invention relates to a granulate whose granulate particles comprise cellulose-containing fibers, a method for producing the granulate, and a feed mixture for animals.

[0002] For various reasons, liquid additives are used in compound feed for livestock, for example, to increase the calorie content of the feed or to supply the animals with important nutrients such as fatty acids, fat-soluble vitamins, or amino acids. Additionally, many liquid feed components have a positive effect on the development of gut bacteria.

[0003] To improve the transport, dosage, handling, and incorporation of these liquid components into the feed mixture, they are typically applied to a solid carrier material. This carrier material is then mixed into the feed mixture.

[0004] The carrier material must be able to bind sufficient quantities of liquid. When loaded, it must be free-flowing. The liquid must be released as completely as possible within the animal's digestive tract. Even under pressure or elevated temperature, the liquid must not leak from the carrier material. The carrier material must be able to be mixed into the feed without subsequent separation. The ingredients of the carrier material must be approved for use in animal feed.

[0005] When it comes to binding liquid additives in animal feed, inorganic substances such as diatomaceous earth and other silicates are currently the first choice. These silicates have a particle size of approximately 100 µm and a DOA adsorption according to ISO 19246:2016 of approximately 2.4 ml / g.

[0006] However, the use of these products is increasingly viewed critically. Crystalline SiO₂ poses a health risk by promoting chronic lung diseases. Furthermore, silicon dioxide will be classified as a nanomaterial in the food sector from 2025 onwards. A similar classification is expected for the animal feed sector.

[0007] Currently, biochar or corncob granules are used as organic alternatives. However, these two options offer significantly lower oil-binding capacity compared to inorganic alternatives. Commercially available wood or cellulose fibers have a high oil- or water-binding capacity, but are no longer free-flowing when saturated.

[0008] A study investigating the influence of an organic carrier material in livestock farming on the gut health of the animals being fed can be found in: Florian Quinger, Julia Kern, Astrid Bosse, Jana Seifert, Markus Rodehutscord, Wolfgang Siegert, Effects of carriers for oils in compound feeds on growth performance, nutrient digestibility, and gut microbiota in broiler chickens, Poultry Science, Volume 103, Issue 7, 2024, 103803, ISSN 0032-5791, https: / / doi.org / 10.1016 / j.psj.2024.103803.

[0009] Biodegradable spheres are also known from WO 2021 / 104728 A1. These biodegradable spheres have a spherical shape with a diameter ranging from 1 to 5000 µm. The spheres contain amorphous cellulose with a weight fraction of 1 to 80% and at least 20% by weight of a cosmetic ingredient with a molecular weight greater than 50 g / mol. Furthermore, the spheres are characterized by a water content of less than 10% by weight. The cosmetic ingredients can include, in particular, oils, vitamins, enzymes, carotenoids, bioactive substances, and the like. The appropriately loaded spheres can be used to manufacture cosmetic compositions. In particular, the spheres are used as exfoliating agents. However, the manufacturing process for the spheres is technically complex.

[0010] Furthermore, DE 100 07 566 A1 discloses an absorbent article. The absorbent article comprises, at least partially, cellulose fibers in the form of granules. The granules can be arranged in an absorbent core located between a liquid-permeable top layer and a liquid-impermeable back layer. Thus, the absorbent article forms a hygiene product such as a sanitary napkin or a diaper. The granules are free-flowing, even when saturated with liquid. The granules can be produced by mechanically grinding cellulose or by winding or coagulating cellulose fibers in a humid atmosphere.

[0011] The present invention is based on the objective of providing an improved granulate suitable for mixing into animal feed mixtures, exhibiting outstanding absorption capacity for liquid additives while maintaining free-flowing properties, and being simple and cost-effective to produce. A further objective of the invention is to provide a method for producing such a granulate.

[0012] According to the invention, these problems are solved by a granulate having the features of claim 1 and a method for its production having the features of claim 12. Advantageous embodiments and further developments as well as a feed mixture for animals comprising such a granulate are set forth in the dependent claims.

[0013] A generic granulate, whose granule particles comprise cellulose-containing fibers, is designed so that the granule particles are capable of absorbing at least their own weight in a liquid substance while simultaneously maintaining their free-flowing properties. The determination of the so-called pile height serves to assess whether or not free-flowing properties are maintained.

[0014] A 60 mm diameter sieve is positioned centrally at a distance of 150 mm over a solid metal cylinder with a diameter of 60 mm and a height of 55 mm. The mesh size of the sieve plate is 3 mm if the material being tested has a particle size of less than 3 mm. If the particle size is greater than 3 mm, a sieve plate with a mesh size of 9 mm is used. The material to be tested, in this case the aforementioned granules, is placed on the sieve and stirred slowly and as evenly as possible using a brush. This stirring continues until a geometrically uniform cone of material forms on the cylinder, and this cone remains stable even after further material is added. The height of this cone is then measured in millimeters. The smaller the height of the cone, the more free-flowing the material.According to the invention, the material is considered to have very good flow properties when the pile height is less than 20 mm. Between 20 and 30 mm, the material has good flow properties. Between 30 and 35 mm, the material has moderate flow properties. If the pile height exceeds 35.0 mm, the tested material is considered to no longer have free-flowing properties, i.e., it has lost its flowability.

[0015] The granules contain cellulose-containing fibers. These fibers can be artificially produced or derived from natural products. They can be pure cellulose fibers or fibers containing cellulose and / or cellulose fibers. Plant fibers are particularly preferred for these cellulose-containing fibers. Examples include wood fibers, fibers from annual plants such as straw, cereal husks, and the like, as well as fibers from perennial plants such as cotton, kapok, and the like. Plant fibers are natural products and can therefore be assumed to be safe for consumption by living beings such as animals. Plant fibers are thus suitable as a compound feed additive.

[0016] The granules according to the invention are capable of absorbing at least their own weight in a liquid substance while remaining free-flowing. This means that 100 g of the unloaded granules can absorb at least 100 g of liquid substance, with the pile cone determined according to the above measuring method remaining less than 35 mm. This allows the granules to be transported even when loaded using pneumatic conveying systems, belt conveyor systems, screw conveyor systems, and the like.

[0017] According to an advantageous embodiment of the granules according to the invention, these have a bulk density of 120.0 to 300.0 g / l, preferably 140.0 to 250.0 g / l and particularly preferably 160.0 to 220.0 g / l, wherein the bulk density is determined in particular according to the following measuring method: Provide a cylindrical measuring tube with an inner diameter of 30.0 mm and a cylinder height of 141.5 mm; place a sieve plate with a mesh size of 3.0 mm onto the measuring tube; place a funnel onto the sieve plate and fill the funnel with the granules; pass the granules through the sieve plate until the measuring tube is filled to the top; remove the funnel and the sieve plate and scrape off any protruding granules from the top edge of the measuring tube; and weigh the filled measuring tube and subtract the weight of the measuring tube from the result.

[0018] The bulk density, often also referred to as bulk weight, of granules of this type is comparatively higher. The granules according to the invention are therefore characterized by a particularly low bulk density, which contributes significantly to the increased absorption capacity of said liquid substances while simultaneously maintaining free-flowing properties.

[0019] Such a low bulk density can be achieved by packing the cellulose-containing fibers in the granule particles in a widely spaced manner. This creates capillaries between the cellulose-containing fibers, which contribute to the reduction in bulk density. The liquid substance in question can be absorbed into the cavities formed by these capillaries. The question then arises for those skilled in the art as to how granule particles, comprising cellulose-containing fibers, can be produced that exhibit such a capillary structure. This will be discussed in more detail later.

[0020] Advantageously, the measurement process is repeated several times, for example 2 to 3 times, and an average is calculated from the individual results. This ensures particularly meaningful results. The measuring tube has an internal volume or measuring volume of 100 cm³. The weight determined in grams can then be multiplied by a factor of 10 to determine the bulk density in g / l.

[0021] According to a further advantageous embodiment of the granules according to the invention, the granule particles have a specific surface area of ​​0.5 to 1.0 m² / g, preferably 0.6 to 0.8 m² / g, wherein the specific surface area is determined in particular by gas adsorption using the following measuring instrument: BET-NOVA 2000e gas adsorption measuring instrument from Quantachrome Instruments, Inc. The granules according to the invention are thus characterized by granule particles that have a particularly high specific surface area compared to the prior art. This large specific surface area results, as already explained in connection with the bulk density, from the loosely packed structure of the granule particles. By encompassing said capillaries, the surface area within the granule particles increases, which accordingly leads to an increase in the specific surface area.This also provides more surface area for wetting the cellulose-containing fibers with the liquid substance to be absorbed by the granule particles. This contributes to increasing the absorption capacity for the liquid substance while simultaneously maintaining flowability.

[0022] To perform measurements with the BET-NOVA 2000e gas adsorption analyzer, some preparations are necessary. First, switch on the vacuum pump and the BET instrument itself. Switching on the vacuum pump first prevents oil vapors from entering the instrument. Next, heat the BET instrument to operating temperature. Then, weigh the empty measuring cell using an analytical balance and record the weight. Next, fill the cell with the sample using a funnel. The lower sphere of the measuring cell should be approximately three-quarters full of sample. A sample weight that results in a total surface area in the measuring cell of 1.5 to 2.0 m² is recommended. Clean the funnel with compressed air after each sample filling. All samples must be degassed before measurement. Finally, start the bake-out process.In this process, all unwanted adsorbed gases and vapors are removed from the pore surface. The sample is now prepared. The measuring cells are then rebalanced using an analytical balance, and the result is recorded. The actual measurement process then begins. This process is carried out automatically by the BET instrument. The difference in weight compared to the degassed sample allows the amount of adsorbed gas to be determined, which in turn is a measure of the specific surface area. These results are calculated automatically by the BET instrument.

[0023] A further advantageous embodiment of the granules according to the invention provides that the granule particles are loaded with at least one liquid substance. Thus, not only the granules themselves, i.e., a corresponding "carrier material," are claimed, but also the finished "product." The carrier material serves to carry the liquid substance. Depending on the intended use, various liquid substances can be used. The granules according to the invention can therefore be used not only as animal feed but also for industrial applications, such as oil binders. Thanks to the special properties of the granules according to the invention, comparatively large quantities of liquid can be absorbed, and the loaded granules remain easily processable due to their continued free-flowing properties.

[0024] Preferably, the liquid substance has a water content of less than 15.0% by weight. The substance can therefore be either an oily or anhydrous.

[0025] The liquid substance is particularly well-suited for use with a liquid feed additive, especially in the form of oils, acids, fatty acids, vitamins, amino acids, or alcohols. The unloaded granules can then be used as a carrier for these additives. Granules loaded with such a liquid substance can then be added to feed mixtures. Due to their high absorption capacity, animals fed with these granules only need to consume a relatively small amount of the granules or cellulose-containing fibers to ingest a defined quantity of the liquid feed additive. As previously described, the granules retain their free-flowing properties, allowing for easy handling and precise dosing.The granules according to the invention are also characterized by the fact that the absorbed liquid substance is released almost completely and easily in the digestive tract of the fed animal. Even under pressure and elevated temperature, the liquid substance does not leak from the granule particles. This prevents the formation of a mushy slurry at the bottom of a feed bag. The granules also exhibit low dustiness. The granules can be mixed with other feed components without separation occurring. Cellulose-containing fibers are approved for use in animal feed. The granules according to the invention are capable of carrying a wide variety of liquid feed additives, thus enabling their broad application. It is also conceivable to incorporate various liquid feed additives together into the granules.Different liquid feed additives can be added gradually or in pre-mixed form.

[0026] The granules can be loaded with the liquid substance by methods such as soaking or spraying them. For soaking, the granules and liquid substance can be mixed together in a mixing container. Alternatively, the granules can be thrown into a puddle of the liquid substance and will then absorb it through capillary action. The loaded granules can then be swept up.

[0027] For example, the following substances are suitable for loading the granule particles: oils such as sunflower oil, rapeseed oil, safflower oil, coconut oil, peanut oil, olive oil, essential oils, as well as alcohols such as glycerin, propylene glycol and organic acids such as propionic acid.

[0028] According to a further advantageous embodiment of the granules according to the invention, the cellulose-containing fibers have an average fiber length of between 30 µm and 3.0 mm, preferably between 30 µm and 400 µm, and particularly preferably between 30 µm and 150 µm. The cellulose-containing fibers lie on top of one another within the granule particles. This creates the aforementioned cavities or inclusions. These cavities serve to absorb and carry the liquid substance. The cavities are so small that capillary effects occur. Upon contact with the granule particles, the liquid substance is drawn into the interior of the granules. This improves not only the absorption capacity but also the absorption rate of the liquid substance. The finer and thinner the fibers used, the smaller the pore size or cavity size. Thus, stronger capillary effects can be utilized.By using particularly fine, short, and uniform fibers, the roundness of the granule particles is increased, further improving their stability and flowability. The size distribution of the granule particles can also be influenced by varying the fiber length and diameter. Shorter or finer fibers result in smaller granule particle diameters. Therefore, by using finer fibers, even more liquid substance can be absorbed from a given quantity of granules.

[0029] A further advantageous embodiment of the granules according to the invention provides that the granule particles comprise a binder, wherein the binder is preferably insoluble in the liquid substance when the granule particles are loaded with the liquid substance. Including a binder in the granules improves their stability. All common binders can be used, taking into account the intended use of the granules. If the granules are to serve as a carrier for liquid compound feed additives, binders should be used that can be safely consumed by the animals in question and that are preferably insoluble in the compound feed additive. For example, the following can be used as binders: polysaccharides such as cellulose ethers, particularly in the form of CMC, HPMC, MC, starch, agar, alginate, carrageenan, and the like.Preferably, the liquid substance is oily or anhydrous. If a binder insoluble in the liquid substance is required, water-soluble substances can be used as binders. Using a binder insoluble in the liquid substance has the advantage that the liquid substance cannot leach the binder out of the granule particles. This ensures that the integrity of the granule particles is maintained even when loaded.

[0030] The binder forms a stable network with the cellulose-containing fibers, thus holding them in shape. The hardness of the granules can be adjusted by selecting the appropriate binder and its concentration within the granulate. This allows the hardness of the granules to be specifically increased, enabling them to withstand the pressures resulting from the weight of a column of granules during transport and loading. This prevents the granules from being crushed under their own weight at the bottom of a bulk material. This, in turn, prevents crushed particles from forming a slurry at the bottom and clumping together. Furthermore, it prevents the liquid substance with which the granules are loaded from leaking out.

[0031] To achieve the desired properties, the binder content in the granule particles is preferably 2.0 to 50.0 wt.%, preferably 5.0 to 45.0 wt.% and particularly preferably 8.0 to 40.0 wt.%.

[0032] A further advantageous embodiment of the granules according to the invention further provides that the granule particles comprise at least one additive, wherein the total additive content of the granule particles is in the range of 0.5 to 20.0 wt.%, preferably 2.0 to 15.0 wt.% and particularly preferably 3.0 to 10.0 wt.%.

[0033] Thus, the granules can not only serve to carry the liquid substance but also to absorb the aforementioned additives. If the granules according to the invention are used, for example, as animal feed, solids can also be absorbed by the granules and supplied to the animals. Additives can be used that further improve or specifically modify the properties of the granules. For example, activated carbon can be added as an additive, which improves the stability of the granules as well as their affinity for certain liquids. The additive can be drawn into the cavities between the cellulose-containing fibers together with the binder and / or the liquid substance, for example, if the additive is dissolved or dispersed in the binder or the liquid substance.The additive can also enter the cavities by dry mixing with the granule particles, provided the additive is in powder or particle form and the particle diameter is smaller than the pore size of the granule particles. Alternatively, the additive can be mixed with or applied to the cellulose-containing fibers before the granule particles are produced. In addition to activated carbon, other suitable additives include vegetable carbon and chitosan. Activated or vegetable carbon can be added to increase the formation capacity. Activated carbon is preferable because its finer particles and larger surface area result in smaller and more effective agglomerates at the end of the process. Chitosan can be added to improve the binding capacity of solutions containing small amounts of water, such as crude glycerin, as chitosan binds the water.

[0034] According to a further advantageous embodiment of the granules according to the invention, it is further provided that at least 90% of the particle size distribution of the granules is below 2000 µm. This means that there are hardly any or even no granules with a particle size of 2000 µm or larger. Thus, granules with a particle size between 0 and 2000 µm can be present. The particle size distribution is particularly preferably distributed into two or more fractions. A first fraction with a particle size distribution of 600 to 1000 µm and a second fraction of 1000 to 2000 µm are particularly preferred. The particle size distribution can be controlled, in particular, by the choice of the starting fibers.As mentioned previously, shorter and thinner fibers result in rounder and smaller granule particles, which accordingly improves the absorption capacity for the liquid substance and the flowability.

[0035] For example, when using wood fibers with a maximum fiber length of up to 400 µm in the mixture, it may not be possible to produce a fraction of granules with a particle size distribution of 600 to 1000 µm. However, the wood fibers can be reduced to a fiber length of less than 150 µm using a sieve, thus making it possible to produce a corresponding particle size distribution of the granules in the range of 600 to 1000 µm.

[0036] A process for producing the granules described above according to the invention provides that the granules are produced by build-up agglomeration based on wet granulation of cellulose-containing fibers with at least water, followed by a drying process. The manufacturing process according to the invention gives the granules their outstanding physical properties. As already described, these are the comparatively high absorption capacity for the liquid substance while simultaneously maintaining flowability. The granules obtained in this way are characterized by a comparatively low bulk density and a high specific surface area. This is achieved by the formation of a fine fiber network in the resulting granule particles, whereby the cavities formed between the fibers lead to a strong capillary action.

[0037] Other agglomeration processes, such as compression agglomeration, are known. Compression agglomeration involves producing granular particles by compressing the starting material. However, this manufacturing method is completely unsuitable for producing the granules according to the invention, as it results in the cellulose-containing fibers being packed too densely. This prevents the formation of voids in the fiber network, thus eliminating capillary action. Granules produced by compression agglomeration are therefore characterized by a reduced absorption capacity for the liquid substance and reduced flowability. Only the manufacturing process according to the invention, using build-up agglomeration, allows the production of granular particles according to the invention.

[0038] Granulation can be carried out in conventional mixing or granulating units that allow for agglomeration, either in continuous operation or as a batch process. For example, production can take place in discs, drums, and mixers, or via fluidized bed granulation. Spray granulation can be used with very fine starting fibers suspended in a binder solution. While dry granulation or extrusion can also be used to produce similar granules, the high compaction involved in these processes leads to a reduction in the maximum loading capacity.

[0039] The amount of water used for granulation influences the shape of the final granule particles. The more water added, the more tightly the cellulose-containing fibers are packed during granulation, resulting in particularly narrow cavities. This allows the absorption capacity and rate of the liquid substance to be adjusted depending on the intended application. For example, increasing the water-to-fiber ratio increases the bulk density, but reduces the maximum oil loading.

[0040] An advantageous further development of the method according to the invention provides that the wet granules are dried to a residual moisture content of 1.0 to 15.0 wt.%, preferably 2.0 to 12.0 wt.% and particularly preferably 3.0 to 10.0 wt.%.

[0041] A further advantageous embodiment of the method according to the invention provides that a liquid substance is added to the wet granules during the agglomeration process, or that the dried granules are loaded with the liquid substance after drying. The agglomeration process can also be carried out without the addition of the liquid substance. The dried granules can then be sold, allowing the customer to perform the loading process with the liquid substance themselves. Thus, the customer can use the granules according to the invention for a wide variety of applications. However, the granules can also be loaded with the liquid substance during the agglomeration process. This is particularly advantageous if the granules are to be used as an additive for feed mixtures. In this way, the granules loaded with the liquid substance can be sold directly as a compound feed additive.

[0042] According to a further advantageous embodiment of the process according to the invention, a binder, in particular a binder insoluble in a liquid substance to be absorbed by the granules, is added to the wet granules during the build-up agglomeration or to the dried granules after drying. The addition of the binder to the granules can therefore take place during the build-up agglomeration or afterwards.

[0043] For example, to produce the granules, cellulose-containing fibers can be wet-granulated with water, or with a solution or suspension of the binder, and then dried to the desired final moisture content in a subsequent step.

[0044] A further advantageous embodiment of the process according to the invention provides that, after drying, the granules are sieved to distribute the granule particles into at least two fractions. As described above, the size of the granule particles can vary within the granules. The granule particles can then be divided into two or more fractions by sieving. This makes it possible to produce granules characterized by a comparatively narrow particle size distribution. Particularly preferably, fractions with a particle size distribution of 600 to 1000 µm and 1000 to 2000 µm can be produced in this way.

[0045] According to the invention, a generic animal feed mixture comprising a first fraction of feed particles includes a second fraction consisting of a granulate described above. The granulate according to the invention, loaded with the liquid substance in the form of a liquid compound feed additive, can thus be added to feed mixtures as a further component. The feed particles can be any type of particle used for animal nutrition. For example, the feed particles can be in the form of spheres, pellets, grains, and the like. The granulate according to the invention can be added as a second fraction to such a first fraction of feed particles. This allows for particularly flexible use of the granulate according to the invention in the context of animal nutrition.

[0046] Due to its high absorption capacity while maintaining its flowability, the feed mixture is easy to handle, transport, dose, and incorporate into the feed mixture. Thanks to the comparatively high pressure stability of the granules according to the invention, even when added to feed mixtures, the destruction of the granule particles and the leakage of the liquid feed additive are reliably prevented.

[0047] The size of the granules is preferably adapted to the particle size of the feed particles, such that the granule size and the particle size differ by a maximum of 100%, preferably a maximum of 50%, and most preferably a maximum of 30%. In other words, the granules and the feed particles are thus approximately the same size. This counteracts separation of the two fractions in the feed mixture. The particle size of typical feed particles is also on the order of less than 2000 µm. With a particle size distribution of the granules in the range of 600 to 1000 µm or 1000 to 2000 µm, the risk of segregation between the granules and the feed particles is particularly low.

[0048] The following describes an exemplary embodiment for the production of granules according to the invention. A wood fiber raw material is provided as the starting material. The wood fiber raw material is sieved to a fiber length of less than 400 µm using a plansifter. The fibers are placed in a granulator, and an aqueous solution of carboxymethylcellulose (CMC) with a concentration of 4% is added while continuously mixing. The CMC grade is selected such that the solution has a viscosity in the range of 100 to 1700 mPas. The viscosity is preferably determined using a Brookfield rotational viscometer with spindle 2 at 20 rpm and a measuring time of 30 s. The ideal mass mixing ratio consists of two parts CMC solution and one part wood fibers.

[0049] After the solution has been completely added, the mixture is granulated at a speed of 2000 to 4000 rpm for three minutes.

[0050] After granulation, the resulting granules are dried at 100 to 130°C to the desired moisture content. Ideally, this is less than 10%.

[0051] The desired particle size fraction is then produced by sieving. The resulting granules can hold at least 100 to 150% of their own weight in sunflower oil while maintaining sufficient flowability.

[0052] Further advantageous embodiments of the granulate according to the invention and its manufacturing process will also become apparent from the exemplary embodiments, which are described in more detail below with reference to the figures.

[0053] This shows: Figure 1 is a schematic representation of a granule particle of a granulate according to the invention; Figure 2 is a schematic detail representation of the granule particle; Figure 3 is a flowchart of a method according to the invention for producing the granulate; Figure 4 is a schematic representation of a measuring method for determining the flowability of the granulate; Figure 5 is a diagram showing the absorption capacity of various granulates for sunflower oil and the resulting flowability; Figure 6 is a schematic representation of a device that can be used in a measuring method for determining the bulk density of the granulate.

[0054] The present invention addresses the problem of providing a carrier material for liquid substances that is capable of binding a sufficient quantity of this liquid while remaining free-flowing when loaded. Ideally, the liquid substance should be completely released in the digestive tract of an animal after consumption of the loaded carrier material. The liquid substance must not leak from the carrier material, even under pressure and elevated temperature. The carrier material should be suitable for addition to feed mixtures without causing subsequent separation between the feed components. Furthermore, the ingredients of the carrier material must be approved for use in animal feed. The carrier material should be transportable in both loaded and unloaded states, easy to dose and handle, and easy to incorporate into compound feed.

[0055] Figure 1Figure 1 shows a granule particle 1 of a granulate according to the invention, which functions as said carrier material. The granule particles 1 of the granulate comprise cellulose-containing fibers 2, which are formed into said granule particles 1 by agglomeration. The cellulose-containing fibers 2 form a loose network, so that cavities 9 are formed between the cellulose-containing fibers 2. These cavities 9 are so narrow that they act as capillaries. This results in the granulate made of the granule particles 1 having a particularly high absorption capacity for a Figure 2 The liquid substance shown in Figure 3 exhibits this characteristic. Due to its porosity, the granules are further characterized by a comparatively low bulk density and a high specific surface area.

[0056] Figure 2Figure 1 shows a detailed view of a section of the granule particle 1. The cellulose-containing fibers 2 are visible, for example, in the form of pure cellulose fibers or plant fibers. For example, the cellulose-containing fibers 2 could be wood fibers. Preferably, the cellulose-containing fibers 2 are bonded together by a binder 8. This improves the structural integrity and hardness of the granule particles 1. Figure 2 Figure 3 also shows the liquid substance 3 absorbed by the cavities 9.

[0057] Figure 3 Figure 3 shows a flowchart of a process according to the invention for producing the granules according to the invention. In step 301, a fibrous starting material is provided. This can be a powder made from the cellulose-containing fibers 2.

[0058] In an optional step 302, the fibrous starting material can be sieved. Proven sieving machines, such as plansifters, can be used for this purpose. The sieve used in such a sieving machine can have a mesh size suitable for the specific application. This allows the fiber length of the cellulose-containing fibers 2 to be reduced to a desired degree.

[0059] In a subsequent step 303, the optionally sieved fibers are mixed with water. Depending on the intended use and composition of the granules to be produced, a fixed mixing ratio of fibers to water is used. For example, two parts by mass of water can be mixed with one part fibers, particularly when using wood fibers as the starting material. If corn granules are used as the fiber raw material for the granules according to the invention, the amount of water used should ideally be adjusted to approximately 1.7 times the amount of fibers by weight.

[0060] As alternative step 303* shows, the fibers can also be mixed with a solution or suspension of water and the binder 8 instead of with water. The binder 8 is preferably insoluble in the liquid substance 3.

[0061] In the subsequent step 304, after the specified quantity of water, solution, or suspension has been completely added to the fibers, the fibers and the water, solution, or suspension are stirred at a specified speed for a specified duration. This is the actual agglomeration process. During stirring, the fibers clump together and form the granule particles 1. This agglomeration creates the fine cavities 9, resulting in capillary action that binds the liquid substance 3.

[0062] Alternatively, it is of course possible to start the stirring process while the "ingredients" are being added to a suitable build-up agglomeration machine, so that the build-up agglomeration process begins while the fibers and water (and optionally the binder) are being added. In this case, steps 303 and 304 or 303* and 304 are carried out in parallel (not shown).

[0063] In the subsequent step 305, the resulting granular particles 1 are dried to a predetermined residual moisture content, preferably to a residual moisture content of less than 10%.

[0064] In the subsequent optional step 306, the granule particles 1 can be sieved to obtain several fractions with a desired particle size distribution. This particle size distribution is preferably based on the particle size of feed particles to which the granule particles 1 are to be added to form a feed mixture according to the invention. The granule particles 1 should thus differ only minimally in size from the particle size of the feed particles in order to counteract segregation.

[0065] The granules produced in this way can now be sold to a customer. It is also conceivable to carry out the loading with liquid substance 3 itself, which can be done in step 307. It is also conceivable to carry out the loading with liquid substance 3 during the build-up agglomeration, i.e., during step 304.

[0066] It is already known to use granules, powders, or the like, comprising cellulose-containing fibers, as carrier materials for liquids such as oils. Oil binders are one example. Such particles are already characterized by a comparatively high absorption capacity for oils. However, these substances clump together or form a kind of "sludge" and, consequently, are no longer free-flowing or free-form when loaded. Therefore, such loaded substances can no longer be easily handled or dispensed. With the granules according to the invention, however, this is possible. Thus, the granules loaded with the liquid substance 3 remain free-flowing or free-form.

[0067] According to the invention, the so-called slump cone height SKH is used to assess the flowability, the determination of which is based on the following: Figure 4The following is described. A solid metal cylinder 10 is provided, over which a sieve 11 is arranged at a distance h of 150 mm. The sieve 11 and the solid metal cylinder 10 have a diameter D of 60 mm. The height H1 of the solid metal cylinder 10 is 55 mm. The mesh size of the sieve 11 is 3 mm. If a starting material with a particle size larger than 3 mm is to be tested, a mesh size of 9 mm is used.

[0068] The material to be tested is placed on the sieve 11 and stirred slowly and as evenly as possible through the sieve 11 using a brush. More material is stirred until a geometrically uniform cone 12 has formed on the solid metal cylinder 10, and this cone remains stable even after further material is added. The height of this cone 12 is then measured as the cone height SKH in millimeters. The starting material, or in this case the granules, is considered non-free-flowing if the cone height SKH is greater than 35 mm.

[0069] Figure 5Figure 3 shows a diagram for various granules loaded with sunflower oil as a liquid substance. The sunflower oil loading, expressed as a weight percentage relative to the granule's own weight, is plotted on the abscissa, and the pile height (SKH) in millimeters is plotted on the ordinate. The diagram illustrates the pile height (SKH) over the loading for a granule GL according to the invention with a particle size distribution in the range of 1000 µm to 2000 µm, which is therefore in a comparatively high range, and for a granule GS according to the invention with a particle size distribution in the range of 600 µm to 1000 µm. The diagram also shows the pile height (SKH) for four different reference granules REF1, REF2, REF3, and REF4.The first reference granule, REF1, is Vivapur CS 800 S; the second reference granule, REF2, is Arbocel G-300; the third reference granule, REF3, is Lignocel HBK 300 / 750; and the fourth reference granule, REF4, is Rehofix MK 1000. Reference granules REF1-REF4 are all manufactured by J. Rettenmaier & Söhne GmbH + Co. KG.

[0070] The diagram shows that even with a significantly increasing load of the liquid substance 3, the flowability of the granules according to the invention increases only imperceptibly. The flowability remains even when the granules are loaded with sunflower oil equal to their own weight.

[0071] The granules according to the invention are preferably characterized by a bulk density of 120.0 to 300.0 g / l, preferably 140.0 to 250.0 g / l and particularly preferably 160.0 to 220.0 g / l. Figure 6shows a device that can be used to determine this bulk density. The procedure is explained using the following examples: Figure 6The process is explained below. A measuring tube 4 is provided, which has a measuring volume of 100 cm³. The measuring tube 4 has an inner diameter (ID) of 30 mm and a cylinder height (ZH) of 141.5 mm. A funnel 6 is placed on the measuring tube 4 and filled with the starting material to be tested. The bottom of the funnel 6 is closed with a sieve plate 5. The mesh size of the sieve plate 5 is 3 mm. To facilitate the collection of the particles sieved through the sieve plate 5, an adapter 13 can optionally be provided between the funnel 6 and the measuring tube 4. The starting material is then stirred with a brush through the sieve plate 5 until the measuring tube 4 is filled above the upper edge 7. The sieve plate 5, the funnel 6, and, if applicable, the adapter 13 are then removed, and any excess material is scraped off. Now the measuring tube 4 is weighed.The measuring tube 4 was also weighed in its empty state, so its own weight is known. This weight is subtracted from the actual measurement result to obtain the mass of the starting material accumulated in the measuring volume of the measuring tube 4. This result can be multiplied by a suitable factor to obtain the result in grams per liter. For example, if the weighing result is given in grams, the result can be multiplied by a factor of 10 to obtain the bulk density in grams per liter. Based on... Figure 6 The described procedure is based on DIN EN ISO 60.

Claims

1. Granules, the granule particles of which (1) comprise cellulose-containing fibers (2), wherein the granule particles (1) are able to absorb at least their own weight in a liquid substance (3) while retaining their free-flowing properties, characterized by the fact thatthe granular particles (1) are free-flowing up to a pile cone height (SKH) of 35.0 mm, the pile cone height (SKH) being determined by the following measuring method: - Central arrangement of a sieve (11) with a diameter (D) of 60 mm at a distance (h) of 150 mm above a solid metal cylinder (10) with a diameter (D) of 60 mm and a height (H1) of 55 mm, wherein the mesh size of the sieve base is 3 mm for a starting material to be tested with a particle size of less than 3 mm and the mesh size is 9 mm if the particle size is greater than 3 mm; - Place the granules onto the sieve (11) and stir the granules through the sieve (11) with a brush until a geometrically uniform cone of material (12) has formed on the solid metal cylinder (10), which does not change in height even after further material has been added; and - measure the height of the cone of material (12).

2. Granules according to claim 1, characterized bya bulk density of 120.0 to 300.0 g / l, preferably 140.0 to 250.0 g / l and particularly preferably 160.0 to 220.0 g / l, wherein the bulk density is determined in particular according to the following measuring method: - providing a cylindrical measuring tube (4) with an inner diameter (ID) of 30.0 mm and a cylinder height (ZH) of 141.5 mm; - placing a sieve plate (5) with a mesh size of 3.0 mm onto the measuring tube (4); - placing a funnel (6) onto the sieve plate (5) and filling the funnel (6) with the granules; - passing the granules through the sieve plate (5) until the measuring tube (4) is filled to the top; - Removing the funnel (6) and the sieve base (5) and scraping off any protruding granules from the upper edge (7) of the measuring tube (4); and - Weighing the filled measuring tube (4) and subtracting the weight of the measuring tube (4) from the result.

3. Granules according to claim 1 or 2, characterized by the fact thatthe granular particles (1) have a specific surface area of ​​0.5 to 1.0 m² 2 / g, preferably 0.6 to 0.8 m 2 / g, wherein the specific surface area is determined in particular by means of gas adsorption using the following measuring instrument: BET - NOVA 2000e gas adsorption measuring instrument from Quantachrome Instruments, Inc.

4. Granules according to any one of claims 1 to 3, characterized by the fact that the granular particles (1) are loaded with at least one liquid substance (3).

5. Granules according to claim 4, characterized by the fact that the liquid substance (3) has a water content of less than 15.0% based on the weight of the substance (3).

6. Granules according to claim 4 or 5, characterized by the fact that the liquid substance (3) is formed by a liquid compound feed additive, in particular in the form of: oils, acids, fatty acids, vitamins, amino acids or alcohols.

7. Granules according to any one of claims 1 to 6, characterized by the fact thatthe cellulose-containing fibers (2) have an average fiber length between 30 µm and 3.0 mm, preferably between 30 µm and 400 µm, particularly preferably between 30 µm and 150 µm.

8. Granules according to any one of claims 1 to 7, characterized by the fact that the granular particles (1) further comprise a binder (8), wherein preferably the binder (8) is insoluble in the liquid substance (3) when the granular particles (1) are loaded with the liquid substance (3).

9. Granules according to claim 8. characterized by a binder content in the granular particles (1) in the range between 2.0 and 50.0 wt.%, preferably 5.0 to 45.0 wt.% and particularly preferably 8.0 to 40.0 wt.%.

10. Granules according to any one of claims 1 to 9, characterized by the fact thatthe granular particles (1) further comprise at least one additive, wherein the total additive content of the granular particles (1) is in the range of 0.5 to 20.0 wt.%, preferably 2.0 to 15.0 wt.% and particularly preferably 3.0 to 10.0 wt.%.

11. Granules according to any one of claims 1 to 10, characterized by the fact that at least 90% of the particle size distribution of the granular particles (1) is below 2000 µm.

12. Method for producing a granulate according to any one of claims 1 to 11, characterized by the fact that the granules are produced by build-up agglomeration based on wet granulation of cellulose-containing fibers (2) with at least water and a subsequent drying process.

13. Method according to claim 12, characterized by the fact that The wet granules are dried to a residual moisture content of 1.0 to 15.0 wt.%, preferably 2.0 to 12.0 wt.% and particularly preferably 3.0 to 10.0 wt.%.

14. Method according to claim 12 or 13, characterized by the fact thata liquid substance (3) is added to the wet granules during the build-up agglomeration or the dried granules are loaded with the liquid substance (3) after drying.

15. Method according to any one of claims 12 to 14, characterized by the fact that a binder (8) is added to the wet granules during the build-up agglomeration or to the dried granules after drying, in particular a binder (8) that is insoluble in a liquid substance (3) to be absorbed by the granules.

16. Method according to any one of claims 12 to 15, characterized by the fact that The granules are sieved after drying to distribute the granule particles (1) into at least two fractions.

17. Animal feed mixture comprising a first fraction of feed particles, characterized by a second fraction of a granulate according to any one of claims 4 to 11.

18. Feed mixture according to claim 17, characterized by the fact thatthe size of the granule particles (1) is adapted to the particle size of the feed particles such that the granule size and the particle size differ by a maximum of 100%, preferably a maximum of 50% and particularly preferably a maximum of 30%.

Images